In a disk drive, an analog signal is read from a storage medium, such as a computer hard disk, and is digitized using an analog-to-digital (A/D) converter. The resulting asynchronous digital data is stored in a buffer, from which the asynchronous digital data is sampled. A clock signal controls the sampling to produce synchronous digital data. If the clock signal is out of phase with the synchronous digital data, errors may result in the output digital data.